The invention relates to an artificial split suede leather of nonwoven material for use in, especially, sport and casual style shoes and a process for producing it.
High-quality, microfiber, artificial split suede leather has long been known. It is popular for the manufacture of clothing but not for the manufacture sport and casual style shoes which are produced in large quantities because its generally-stable cost is considerably higher than the greatly-fluctuating price of split cowhide leather at least on downward price fluctuations and this is less tolerable in the production of shoes.
Therefore, there is a market need for a split suede leather-like material which can be obtained at a generally-favorable price, as well as with the uniform quality, appearance, and mechanical properties available from synthetic or artificial manufacture. The latter properties allow a synthetic product in continuous web form to be drawn directly from a roll thereof and cut or stamped into a pattern in several layers simultaneously. In the case of genuine leather, cutting a pattern from the hide must be done on a single hide layer to avoid blemishes and accommodate its shape. This is an expensive and time-consuming procedure and, thus, an obstacle to efficient production. Furthermore, it would be desirable for the mechanical properties of the synthetic to avoid the disadvantages of genuine leather, such as sensitivity to moisture, lack of color fastness, and non-machine-washability.
Fibers having a trilobate, Y-shaped cross section are described in Handbuch der Textilverbundstoffe by R. Krcma (1970) on pages 151 to 154. From this, and from French Pat. No. 1,439,288 (F.B. Mercer Ltd.), it is known to use such polyamide fibers for their advantageous effect on the loft and mechanical/physical properties of a needled nonwoven. However, the only areas of use described for the trade are for clothing, carpet tufting and hosiery. Suitability for artificial split suede leather is nowhere mentioned, nor is it obvious, on account of the different characteristics required for split suede leather-like material. Furthermore, the literature always mentions crimping and shrinking as important characteristics of such trilobate fibers.